How Coronavirus Mutations Take Over

The more people infected with the virus, the more likely it is to develop, according to Theodora Hatziioannou, a Rockefeller University virologist studying the new variant.

Since the beginning of the pandemic, scientists using SARS-CoV-2 samples collected around the world have cataloged these genetic mutations. This enabled them to set up a family tree that shows how the virus develops.

Here are some milestones in the evolution of the Covid-19 virus and how adaptations to the genetic code have led to the new, potentially more contagious strains making the world go around:

Decisive mutation

Early last year, scientists detected a mutation in Europe that makes the virus more transmissible than the original versions found in China.

The mutation, called D614G, changes the shape of vein proteins on the surface of the virus, making it more effective at binding and infecting cells.

Variants with the D614G mutation quickly overtook earlier versions of the virus.

“By June, it had replaced the ancestral virus,” said Jeremy Luban, a virologist at the University of Massachusetts Medical School who studied the mutation. “Everywhere it went, it became the dominant tribe.”

Summertime Spread

A new variant, known as 20E (EU1), was first detected in Spain last summer.

It has since spread widely in Europe.

20E (EU1) does not appear to have mutations that make it more transmissible than early variants. On the contrary, it may have been just the right place at the right time – a popular European holiday destination at the height of summer. ‘It could be during the summer trips, it could be because you got rid of all your restrictions, or it could be more transferable,’ said Emma Hodcroft, an epidemiologist at the University of Bern in Switzerland, who conducted a study led about the variant.

The new variants

The variants that have recently been detected in the United Kingdom and South Africa have several new changes in their protein genes.

Scientists think that one mutation that shares these variants could help the virus bind to and invade cells. The recent variant from Brazil has an important vein protein mutation with the one from South Africa.

“What we see is exactly what we expect to see. The surface proteins of the virus are under tremendous pressure to change, ”said Sean Whelan, a virologist at Washington University in St. Louis. ‘All that the virus really pays attention to, multiplies … If it enters the cells of the [host] and avoiding that host’s immune system will increase it. Whether it causes disease is another question. ”

Some scientists are concerned that the variant from South Africa may be better at evading antibodies produced as a result of natural infection and vaccination.

Preliminary estimates suggest that the UK variant is 50% -70% more transmissible than earlier versions of the virus. And British scientists recently said that early data suggests it could also be more deadly.

The variants found in the United Kingdom and South Africa have become the dominant species in countries where they were first detected.

The variant from the United Kingdom has spread widely abroad. At the end of January, there were reports in 70 countries and territories. The variant from South Africa has been reported in more than 30.

The variant from the United Kingdom was detected in more than two dozen US states until the end of January.

The Centers for Disease Control & Prevention has predicted that it could become the dominant domestic tension by mid to late March, unless steps are taken to slow it down. The variants first found in South Africa and Brazil have also been found in the USA.

The full extent of its distribution is difficult to measure. Apart from the United Kingdom and Denmark, few countries with active outbreaks have done the genetic sequencing of the virus, Drs. Hodcroft said.

“Right now, almost the rest of the world is a blind spot.”

Additional sources: Nextstrain (phylogenetic trees); Emma Hodcroft, University of Bern

Write to Daniela Hernandez by [email protected]